Re: Did Chevy consider Packard V8 BB Design?

Posted by 55PackardGuy On 2008/10/10 23:08:35

Jack and Craig,

Some of these specs are beyond me, but they mean a lot to some technical folks who can appreciate them.

I'm back in the dark ages of HP and Torque. I have the published figures for the Packard 352, and wonder if the same categories are easily obtained for the 348 W ? I think that engine would be most comparable to the 352 Packard, and most likely to be the "platform" on which Chevy might have decided to base an engine. So I vote for 352 vs 348 comparison using the same spec categories as Packard offered.

I understand those spec categories (and VE somewhat) but this is the one that gets me:

What the heck is Maximum B.M.P.E., lbs/sq in 152.1@ 2600 rpm??

I will also continue to look around for 348 W Chevy specs.

(Mere hours later...)

Well, that didn't take long. It's not as exhaustive as the Packard list, but it's a start.

1958 Chevy 348 with 4 bbl
Bore & Stroke 4.125 x 3.25
Compression Ratio 9.50:1
HP 250 @ 4400
Torque 355 @ 2800
Firing Order 1-8-4-3-6-5-7-2
Weight* 655
*According to "Super Cars" December 1978
(All other specs from "Carnut" web site)

Since they're back on a previous page, here for your convenience are the Packard 352 figures:

Bore 4"
Stroke 3.5"
Stroke-to-Bore Ratio .875
Displacement 352 ci
Compression ratio 8.5:1
Designation of Cylinders:
Left F-R 1-3-5-7
Right F-R 2-4-6-8
Firing Order 18436572
Maximum Gross Brake HP 260 @4600 rpm
Maximum Gross Torque 355 ft/lbs @2400-2800 rpm
Maximum B.M.P.E., lbs/sq in 152.1@ 2600 rpm
Piston Travel 1480 ft/mi
Engine weight 698 lbs

According to this, even though the Packard gives up a full point on compression ratios, it bests the Chevy by about 10 HP at 200 higher rpm and has identical torque in a range starting 400 rpm lower than the Chevy and, according to the specs, staying in that range up to the same rpm where the Chevy peaks

It does all this while weighing 43 lbs more than the Chevy (although weights can be measured under so many different configurations, it's pretty hard to tell.

Maybe Chevy decided they wanted something that would behave very much like the Packard!

Now here's a question. Chevy started touting later editions of this engine as the "Turbofire", which I thought they meant to indicate was something new in the firing order--but all the BBs had the same firing order. The SBC, too.